Barrier layer formation for conductive feature

Abstract

Embodiments described herein relate generally to one or more methods for forming a barrier layer for a conductive feature in semiconductor processing. In some embodiments, an opening is formed through a dielectric layer to a conductive feature. A barrier layer is formed in the opening along a sidewall of the dielectric layer and on a surface of the conductive feature. Forming the barrier layer includes depositing a layer including using a precursor gas. The precursor gas has a first incubation time for deposition on the surface of the conductive feature and has a second incubation time for deposition on the sidewall of the dielectric layer. The first incubation time is greater than the second incubation time. A conductive fill material is formed in the opening and on the barrier layer.

What is claimed is: 
     
       1. A method of forming a semiconductor device, the method comprising:
 forming an opening through a dielectric layer to a conductive feature; 
 forming a barrier layer along a sidewall of the dielectric layer and an upper surface of the conductive feature, wherein forming the barrier layer comprises: 
 forming a first sub-layer along on the sidewall of the dielectric layer and on the upper surface of the conductive feature, wherein a first thickness of the first sub-layer on the sidewall of the dielectric layer is greater than a second thickness of the first sub-layer on the upper surface of the conductive feature, wherein the first thickness is greater than the second thickness; and 
 forming a plurality of additional sub-layers on the first sub-layer, wherein each of the plurality of additional sub-layers has a difference between a thickness of a respective one of the plurality of additional sub-layers over the sidewall of the dielectric layer and a thickness of the respective one of the plurality of additional sub-layers over the upper surface of the conductive feature is less than a difference between the first thickness and the second thickness; and 
 forming a conductive material over the barrier layer; 
 wherein forming the barrier layer comprises, after forming the plurality of additional sub-layers and prior to forming the conductive material, performing a plasma treatment. 
 
     
     
       2. The method of  claim 1 , wherein the plasma treatment comprises a hydrogen plasma treatment. 
     
     
       3. The method of  claim 1 , wherein after the plasma treatment, an uppermost sub-layer of the plurality of additional sub-layers has a greater density than the first sub-layer. 
     
     
       4. The method of  claim 1 , wherein after the plasma treatment, each of the plurality of additional sub-layers has a greater density than the first sub-layer. 
     
     
       5. The method of  claim 1 , wherein after the plasma treatment, the first sub-layer has a higher carbon concentration than the plurality of additional sub-layers. 
     
     
       6. The method of  claim 1 , wherein as deposited, the first sub-layer has a higher carbon concentration than each of the plurality of additional sub-layers. 
     
     
       7. A method of forming a semiconductor device, the method comprising:
 forming an opening through a dielectric layer to a conductive feature; 
 forming a barrier layer along a sidewall of the dielectric layer and an upper surface of the conductive feature, wherein forming the barrier layer comprises:
 forming a first sub-layer along the sidewall of the dielectric layer and on the upper surface of the conductive feature, wherein a first thickness of the first sub-layer on the sidewall of the dielectric layer is greater than a second thickness of the first sub-layer on the upper surface of the conductive feature, wherein the first thickness is greater than the second thickness; and 
 forming one or more additional sub-layers on the first sub-layer, wherein forming each of the first sub-layer and one or more additional sub-layers comprises
 performing one or more pulsing cycles, wherein each of the one or more pulsing cycles comprises pulsing a carbon-containing precursor gas and pulsing a reactant gas; and 
 reducing a concentration of carbon in the carbon-containing precursor gas; and 
 
 forming a conductive material over the barrier layer. 
 
 
     
     
       8. The method of  claim 7 , wherein pulsing the carbon-containing precursor gas is performed prior to pulsing the reactant gas. 
     
     
       9. The method of  claim 7 , wherein pulsing the reactant gas is performed prior to pulsing the carbon-containing precursor gas. 
     
     
       10. The method of  claim 7 , wherein forming the barrier layer further comprises performing a plasma treatment, the plasma treatment densifying at least an uppermost sub-layer of the one or more additional sub-layers. 
     
     
       11. The method of  claim 10 , wherein the first sub-layer and the one or more additional sub-layers comprises tantalum nitride. 
     
     
       12. The method of  claim 7 , wherein the carbon-containing precursor gas comprises Ta,[(3,4-eta)-alkyne] tris (N,N-alkylaminato) (Ta[N(CH 3 ) 2 ] 3 (C 6 H 10 )) or Ta[N(C 2 H 5 ) 2 ] 3 NC(CH 3 ) 3 . 
     
     
       13. The method of  claim 7 , wherein:
 pulsing the carbon-containing precursor gas comprises pulsing a carbon-rich tantalum nitride precursor gas and a carbon-poor tantalum nitride precursor gas, and 
 reducing the concentration of carbon in the carbon-containing precursor gas comprises reducing a ratio of a flow of the carbon-rich tantalum nitride precursor gas to a flow of the carbon-poor tantalum nitride precursor gas. 
 
     
     
       14. A method of forming a semiconductor device, the method comprising:
 forming an opening through a dielectric layer to a conductive feature; 
 forming a barrier layer along a sidewall of the dielectric layer and an upper surface of the conductive feature, wherein forming the barrier layer comprises forming a plurality of sub-layers along on the sidewall of the dielectric layer and on the upper surface of the conductive feature, wherein a first thickness of a lowermost sub-layer on the sidewall of the dielectric layer is greater than a second thickness of the lowermost sub-layer on the upper surface of the conductive feature, wherein forming each of the plurality of sub-layers comprises pulsing a carbon-containing gas and pulsing a reactant gas; and 
 forming a conductive material over the barrier layer. 
 
     
     
       15. The method of  claim 14 , wherein forming the plurality of sub-layers comprises reducing a carbon concentration of the carbon-containing gas. 
     
     
       16. The method of  claim 14 , wherein the carbon-containing gas comprises a carbon-rich gas and a carbon-poor gas. 
     
     
       17. The method of  claim 16  further comprising decreasing a flow of the carbon-rich gas and increasing a flow of the carbon-poor gas. 
     
     
       18. The method of  claim 14  further comprising, prior to forming the conductive material, performing a plasma treatment to densify at least an uppermost sub-layer of the plurality of sub-layers. 
     
     
       19. The method of  claim 14 , wherein the reactant gas comprises ammonia or hydrazine.